This invention relates to a removable cover assembly for open containers or the like. More particularly, the present invention relates to a roll-up tarp apparatus for an open truck box or trailer.
Roll-up tarp apparatus for truck and trailer bodies having an open top are widely utilized in the trucking industry. For example, U.S. Pat. No. 4,302,043 discloses a roll-up tarp for trailers having a tarp secured to one longitudinal top edge of the truck box or trailer while the opposite edge of the tarp is affixed to a tube which extends the length of the trailer. The rear of the tube is attached to a universal joint which in turn is attached to a crank handle such that the tube can be rolled transversely across the top of the truck box. When the tarp is unrolled, the tube rolls over a latch plate attached along the longitudinal top edge of the truck box on the opposite side of the vehicle from where the tarp is secured. The tube is then wound in an opposite direction such that the tarp is wedged between the latch plate and the truck.
This method of securing the tarp in a covered position has several problems associated with it, some of which are discussed below. Firstly, there is a problem with tarp wear as the tarp is constantly rubbing against the latch plate and the truck box when in the covered position. Additionally, during the wedging process, the fabric has a tendency to pinch and bunch up between the tube and the plate so as to create a force opposing the tightening of the tarp. This makes it difficult to fully tighten the tarp and frequently results in a tarp which is not very tight. Furthermore, the tarp has a tendency to loosen during transit. This is especially true if an excessive amount of cargo is loaded into the truck box so as to be heaped above the height of the framework which supports the tarp. During transit, the load will settle resulting in a loose tarp which may accidentally release causing a road hazard. The binding of the tarp between the roll tube and the latch plate further creates an unwanted strain on the crank handle so as to cause a spring-loaded effect which makes the handling of the crank handle somewhat hazardous when releasing the crank handle from the retainers at the back of the truck.
U.S. Pat. No. 4,212,492 discloses a roll-up cover apparatus which is retained in a covered position by straps which must be individually attached to the side of the vehicle and tightened. In addition to other problems, tightening of the individual straps is time consuming and often does not result in a uniformly tight cover apparatus.
The present invention solves these and many other problems associated with the art.